Beyond his role as a judge, what unique action, driven by a specific vow, significantly impacted the life and legacy of Jephthah, as detailed in the Book of Judges?

A He negotiated a peace treaty with the Ammonites based on shared religious practices. B He dedicated his life to rebuilding a destroyed altar to Yahweh, inspiring national repentance. C He sacrificed the first thing to come out of his house, fulfilling a rash vow to God, which tragically turned out to be his daughter. D He led a military campaign to conquer new territories, expanding Israel's influence and wealth.